Design and analysis of gasket cutting machine

13 Pages·2016·1.03 MB·English

p-ISSN : 2335-1357 e-ISSN : 2437-1122
M J
Mediterranean Journal of Modeling and
Simulation
M S
Med. J. Model. Simul. 05 (2016) 046-058
Design and analysis of gasket cutting machine
Vipin V. Gopal a , Lokavarapu Bhaskara Rao a
(cid:3)
a School of Mechanical and Building Science, VIT University, Chennai Campus,
Vandalur-Kelambakkam Road, Chennai, Tamil Nadu, India
ARTICLE INFO ABSTRACT
Article history : Paper is about the design and analysis of the optimized gasket cutting
Received October2015 machine which can be provide to the companies where there is use of
Accepted February 2016 gasketsatacertainintervaloftime.Thepapercontainthecostoptimized
machinewhichisprovideatamuchlowercostascomparedtothemachines
Keywords : presentlyavailableinthemarket.Thismachinecanbespeci(cid:133)callyusedfor
Gasket; theboilerandrefrigerationcompanieswherethegasketsareusedtoavoid
Fully automated; the leakage due to the joining of two di⁄erent diametric pipes. Inspite of
Idealization ofsystem; giving a large order of gaskets, they can prepare the same at small rate
Cost analysis; wheneverneeded at the location.
Designformanufacturingandassem-
bly. c2016 LESI.Allrights reserved.
(cid:13)
1. Introduction
Gasketisamechanicalsealthatisusedfor(cid:133)llingthespacebetweentwosurfaces,usually
to prevent the leakage between the two objects which is under compression. Gaskets are
used to cover irregularities on mating surfaces of machine parts. They are commonly
produced by cutting from sheet materials such as paper, rubber, silicon, metal, (cid:133)ber and
asbestos lining material (L. Angrisani et al, 1999).
The use of gaskets in automobiles, chemical plants, power plants, ship building yard,
breweries, dye, stu⁄plants, oil re(cid:133)neries, refrigeration plants, allied industries, assembly
lines in refrigeration plants etc (Trelleborg sealing solution,2011). In refrigeration and air
conditioning system during assembly of the pipes di⁄erent diameters pipes are bolted
together (David A. Nash et al, 2009; Dennis R. Moss et al, 2012). During joining the
two di⁄erent diameters pipe there is a possibility of leakage due to improper contact
between them. During assembly there is a major problem of leakage of refrigerant leads
to decrees the internal pressure and (cid:135)ow rate of refrigerant. These gaskets get degraded
after a speci(cid:133)c life time. And for the replacement the companies have to order the same
in a bilk. So, rather than buying the gasket the company can have one of the machines
so that they can make the gasket whenever needed. But in market the gasket machine
Email : [email protected]
(cid:3)
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is available at 30,000-50,000 INR (471- 785 USD). In this paper design of the machine
which can cuts gasket rings of di⁄erent diameters as per requirement.
The machine can be operated manually and can be designed to cut gasket of di⁄erent
diameters and sizes with proper accuracy of +/- 1mm by using this special purpose
machine the gasket rings of di⁄erent diameters can be cut and used in assembly line. The
gasketsheetsupto3mmto5mmthicknesscanbecutwithproperaccuracy. Themachine
doesn(cid:146)t require any kind of external supply. It doesn(cid:146)t need electric power to run, so it
can be used in remote area also. Or otherwise the machine can be operated manually,
semi-automated or fully automated depending upon the need. The machine is portable
and simple in working.
2. Numerical modeling
Designing is the process of developing a product followed by generation and evaluation
of the same. The designing process includes identi(cid:133)cation, re(cid:133)ning, evaluating and then
the documentation of the designed product. The design procedure is well depicted in
Figure 1.
Fig. 1 (cid:150)Design procedure.
2.1. Design consideration
Forthedesigningofthegasketcuttingmachineitwasnecessarytoassignsomeconstant
parameters for the initial designing procedure (James Walker Moor(cid:135)ex). So, for the same
in this paper the diametric range of the gasket ring is considered to be 50mm to 300mm
and an accuracy of +/- 1mm. The maximum thickness of the gasket sheet is considered
to be 5mm. The length of the guide way is 700mm and height of the machine is 250mm.
The main factor of consideration is the ovality; there should be no ovality error.
2.1.1. Design and description of the di⁄erent components
The machine consist of base frame subassembly that contains L-angle guide ways on
which disk can be slide the supporting panel of the machines that are front supporting
plates and L-shaped plates to support the total weight of machine and hold it at proper
ground clearance (M.F. Spotts et al, 2011).
Another sub assembly contains the supporting disk with its mountings. On the guide
ways the sliding support can be (cid:133)xed which can slides the disk as per requirement. Above
that the disk holder can be placed which holds the disk in proper manner. On which the
diskismountedwhichbothcanhaveslidingaswellasrotatingmotionduetoarrangement
of bearing. To hold the gasket in proper position above the disk the ovality reducer is
placed which can be (cid:133)tted by screw and thread arrangement.
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Fig. 2 (cid:150)Design model of the gasket cutting machine (Catia User Manual).
Fig. 3 (cid:150)Schematic model of gasket cutting machine.
There is another arrangement of roller which can also sides along disk on guide ways
with disk. It helps to support the disk at the load side to reduce its tilting e⁄ect towards
the load side. The cutting operation can be done by carbide tip cutter mounted on the
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solid shaft at its end. Which can be pressurized by the nut and screw arrangement its
head. The shaft is pivoted at one support close to its other end. It consists of handle
which can used to rotate the shaft. By simply rotating it the cutting operation can be
done. The design model of the gasket cutting machine is shown in Figure 2.
The gasket cuttig machine was modeled taking into consideration, the conventional
geomertyofthemodel.Thenewcharacteresticswasachievedbyintroducinganinnovative
idea of reducing the number of parts and reducing the complexity of the design by using
a simple design. The nuber of parts used is less as compared to the previous design. The
concepts of design for manufacturing and assembly is been greatly used. The circular base
10 for mounting the raw material is made more dynamically sound by applying necessary
constraints.
The constrains can be added or removed according to the work application. To avoid
the sagging or bukling of the raw material during cutting a ball indenter support 11 is
provided. This innovative design lets the new design to stand out of the crowd because of
its uniqueness. FIG. 3 shows the respective view of the gasket cutting machine consist of
two L-angle bars 4 which is supported by L shaped plates 7 on one end and rectangular
shaped plate 12 on other end. These ensures the stability of the parts above the L-angle
bar and provide a good support to the system.
The front frame according to the embodiment includes a ciruclar disc plate 5 on the
bars on which the raw materials kept inorder to cut gaskets. These are attached to the
bars with the help of the disc support 11 which is tightend with the help of screw. Now
a shaft 2 is used in which to the end the carbide tool 10 can be (cid:133)xed which is useful for
cutting the gasket. To the other end of the shaft consist a handel 1 which makes it useful
during the period of power cuts. The gasket cand me cut by rotating the handel too.
This shaft is held in a position by using two blocks; one is bearing block 3 and another
one is couple block . These two consists of bearing house which enhances the easy rotation
oftheshaft.Figurealsoshowscoupleblockwhichcontainsapowerscrew9whichprovides
or which is used to maintain the essential pressure needed to cut the gasket. By rotating
the power screw we can change the pressure because as we rotate the screw it pressurises
the shaft to bend thus applying pressure on the gasket material.
The assembly consisting of the ball indenter which is used to provide an essential
reaction or support to the gasket material to avoid sagging or bending of material due to
the application of force by the cutter. To the bottom a shaft or pulley is attached to the
disc down support 11 through which a belt is attached which is inturn connected to the
motor which can be used to rotate the disc which will appreciate the use of automatic
cutting of gasket. The shaft consisting of the tool can be moved linearly to adjust the
diameter of the gasket that is to be made.
3. Analysis
The next step after designing is to do the analysis of the product. In earlier days, for
analysis one has to actually make a prototype which is actually a very lengthy process
and waste of time. But the modern technology has provided the easy way of analyzing
the design with the help of software(cid:146)s. Analysis is an essential process as it helps in
determining the major failure parts of the system under study. The use of software(cid:146)s has
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made it easy to check the actual failures same as if the design would have been subjected
to the actual working conditions. For the analysis using software(cid:146)s one has to idealize the
system geometry, (cid:133)eld conditions, boundary conditions etc and the results so obtained
from the analysis are next to accuracy and it will or may di⁄er from other software(cid:146)s as
the solvers used by the software way di⁄er. The results may di⁄er but the di⁄erence in
the results will be very less.
3.1. Mesh
The analysis of the system was carried out using Ansys software. For the analysis to
start it is very important to mesh the design which has been imported. Meshing is the
process of discretizing the model into small distinct parts. Finer the mesh more accurate
will be the result. The meshing used is the tetrahedral mesh and the meshing is shown in
Figure 4.
Fig. 4 (cid:150)Meshing of the designed part (Ansys workbench).
The respective number of nodes and elements generated is shown in Table 1. As the
mesh count increases there is an increase in number of nodes and element.
Table1(cid:150)Showsthenumberofelementandnodeobtainedinmeshing(Ansysworkbench).
Statistics
Nodes 124043
Element 62990
Mesh metric None
After doing the meshing it is necessary to give essential boundary conditions such as
the end conditions, forces moment etc to get the accurate result (Koji Teramoto et al,
1998; Edgar R., 2012). The boundary conditions applied to system are; a pressure of 398
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Pa is applied on the plate due to cutter, a reactant force of 50 N is applied by the ball
indenter support, and legs of the system are (cid:133)xed. The boundary conditions fed to the
software is shown in Figure 5.
Fig. 5 (cid:150)Boundary condition given to the design (Ansys workbench).
The values of the forces applied to the model as shown in Figure 5 are given in the
Table 2.
Table 2 (cid:150)Values of the boundary condition applied to the model (Ansys workbench).
Object name Pressure Force Fixed support
State Fully de(cid:133)ned
Scope
Scoping method Geometry selection
Geometry 1 face 2 face 3 face
De(cid:133)nition
Type Pressure Force Fixed support
De(cid:133)ne by Component
Coordinate system Global coordinate system
X component -398 Pa (ramped) -50 N (ramped)
Y component 0 Pa (ramped) 0 N (ramped)
Z component 0 Pa (ramped) 0 N (ramped)
Suppressed No
3.2. Results
After giving the all the essential boundary conditions and running for the results. The
(cid:133)rst is the deformation result, it is found that the maximum deformation obtained is
0.004 mm which is a very small de(cid:135)ection and can be neglected. The following de(cid:135)ection
is shown in Figure 6.
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Fig. 6 (cid:150)Deformation of the designed model (Ansys workbench).
The maximum value of stress induced in the designed model is 1.6765e7 Pa; whereas
the maximum allowable stress for the model is 2.5e8 Pa. Thus, the model is safe as per
stress point of view and is shown in Figure 7.
Fig. 7 (cid:150)Von-Mises stress analysis of the designed model (Ansys workbench).
Similarly, the maximum value of strain subjected to the model is 9.3733e-5 m/m, while
the actual value is 4e-6 m/m. Thus the model is safe and is shown in Figure 8.
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Fig. 8 (cid:150)Von-Mises strain analysis of the designed model (Ansys workbench).
According to the results obtained from the results, the maximum and the minimum
values of the desired parameters and the area of e⁄ect is shown in Table 3.
Table 3 (cid:150)Maximum and minimum values of deformation, equivalent stress and strain
(Ansys workbench).
Object name Equivalent stress Equivalent strain Totaldeformation
State Solved
Scope
Scoping method Geometric selection
Geometry Allbodies
De(cid:133)nition
Type Equivalent (von-Mises) stress Equivalent elastic strain Totaldeformation
By Time
Display time Last
Calculate time history Yes
Suppressed No
Integration Point Result
Display option Averaged
Results
Minimum 1.2753e-008 Pa 1.2536e-019 m/m 0 m
Maximum 1.6765e+007 Pa 9.3733e-005 m/m 4.1528e-005 m
Minimum occurs on Shaft Down support
Maximum occurs on Gasket indenter Circulardisc
3.3. Idealization of the results
From the results which were obtained from the analysis of the designed model it is
clear that the maximum deformation occurs in the disc. Therefore, analysis for the disc
alone was done by using Ansys APDL. Both Ansys classical and workbench are used for
the analysis purpose but for more theoretical results Ansys classical are used but work
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industrial application workbench are used. The same boundary conditions were given for
the analysis as it was given during workbench except the (cid:133)xed support i.e., a pressure of
398 Pa is applied on the plate due to cutter, a reactant force of 50 N is applied by the
ball indenter support and the centre of the disc is constrained with all degrees of freedom.
The boundary conditions so given are shown in Figure 9.
Fig. 9 (cid:150)Boundary conditions given to the disc (Ansys APDL).
The main concern is with the deformation of the disc. The analysis was carried out and
the deformation seemed to be 0.011484 mm which is a negligible value and hence can be
neglected. The deformation of the disc is shown in Figure 10.
Fig. 10 (cid:150)Deformation of the disc (Ansys APDL).
The results obtained from both the analysis were satisfying and was well beyond the
limits and hence is safe. Thus the structure can be used for the industrial applications.
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4. Cost Analysis
In order to sell the product in a market, the product should have enough qualities. One
of such factor is the cost (Bryan R. et al, 2011; G. Boothroyd et al, 1993). When it comes
to the market survival and to compete with the other companies it is necessary that the
product should attract the customers and the (cid:133)rst factor which attracts the customers is
the cost of the product. The products are required to be manufactured at the lower cost
and with good qualities.
4.1. Manufacturing methods
The important factor which decides the cost of the part is the cost of machining or
di⁄erent manufacturing process used for manufacturing the respective parts. The manu-
facturing process of the parts required for the model has been explained in Table 4.
Table 4 (cid:150)Manufacturing methods of the parts.
Sr.No : PARTS PROCESS
1. Power hacksaw
1 Shaft 2. Facing
3. Turning
1. Gas cutting
2 Side plate 2. Grinding
3. Drilling
1. Cutting
3 L angle 2. Grinding
3. Drilling
1. Power hacksaw
4 Bearing block 2. Drilling
3. Boring
4. Turning
1. Power hacksaw
5 Nut Block 2. Drilling
3. Threading
4. Turning
1. Power hacksaw
6 Guide way upper plate 2. Drilling
3.Threading
1. Power hacksaw
7 Supporting roller 2. Drilling
3. Threading
4. Welding
8 Circular disc 1. Gas cutting
2. Drilling
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